1. Field of the Invention
This invention relates to a thermoelectric module which performs thermoelectric conversion, and to a manufacturing method for same.
Priority is claimed on Japanese Patent Application No. 2005-37767, filed Feb. 15, 2005, the content of which is incorporated herein by reference.
2. Description of Related Art
Thermoelectric modules, which utilize the Peltier effect and the Seebeck effect in thermoelectric power conversion, have conventionally been used in heating and cooling equipment and other applications. Such thermoelectric modules are configured by forming multiple electrodes at prescribed locations on the opposing inside surfaces of a pair of insulating substrates, and by soldering the upper and lower ends of thermoelectric elements to the opposing electrodes, to fix in place multiple thermoelectric elements between the pair of insulating substrates.
Among such thermoelectric modules, there are devices having a structure which prevents the occurrence of short-circuits across electrodes due to the flow of solder in the molten state on the insulating substrates when soldering the thermoelectric elements to the electrodes. Among these devices, there are thermoelectric modules in which electrodes are configured from three layers, which are a copper layer, a nickel layer formed over the entire surface of the copper layer, and a metal plated layer of gold or similar formed on the upper surface (the upper surface when forming the electrodes) of the nickel layer, and in which the nickel layer which has less solderability is exposed on the side surfaces of the electrodes (see for example, Japanese Unexamined Patent Application, First Publication No. 2004-140250).
There are also devices in which grooves are provided between the electrodes on the insulating substrates, to prevent the flow of solder in the molten state onto other electrodes (see for example, Japanese Unexamined Patent Application, First Publication No. 2003-100983).
However, of the above-described thermoelectric modules, the former entails the difficulty of processing to cause the nickel layer to be exposed on the side faces of the electrodes, as a result of which there are the problems that the number of processes is increased, production yields are lowered and manufacturing times lengthened, and in addition costs are increased. In methods to manufacture such thermoelectric modules, prior to removal by etching of the unwanted portions of the metal plated layer (the side-face portions of the electrodes), resist is formed on the upper surface of the metal plated layer; and there is the problem that during this processing, a shift in the electrodes and mask causes resist to touch the side faces of electrodes, giving rise to short-circuits.
Further, in the case of the latter thermoelectric modules of the prior art, grooves are formed between the electrodes on the insulating substrates respectively, so that the distances between electrodes are increased, and there is the problem that the thermoelectric modules are increased in size (with reduced densities). Moreover, because grooves are formed, the number of processes is increased, production yields are lowered and manufacturing time is prolonged as well as increased costs.
The present invention was devised in order to address the above-described problems, and has as an object the provision of a thermoelectric module and manufacturing method for a thermoelectric module capable of preventing short-circuits between electrodes due to solder, without resulting in increases in size or cost.